1. Field of the Invention
The present invention relates to a glass disk processing method of polishing the inner and outer peripheral faces of a glass disk stacked body in which a plurality of glass disks are stacked.
2. Description of the Related Art
As a magnetic disk is becoming smaller and having higher density, a glass disk having excellent surface smoothness and excellent mechanical strength is often used for an information recording medium. The glass disk for an information recording medium is generally processed by performing coarse processing using a diamond cutter or a core drill, precision finishing using a diamond wheel, and polishing of the inner and outer peripheral faces of the glass disk with a polishing pad or brush.
In recent years, to record/reproduce information at higher density, the interval between a magnetic head and the recording surface of a glass disk is narrowed. As a result, when the magnetic head travels in the lateral direction, if even a small projection exists, there is the possibility that the magnetic head collides with the side face of the glass disk. To avoid such collision, the corners formed by the upper and lower recording faces and the side face undergo edging process such as chamfering or rounding. A technique is disclosed such that, as the edging process on the corners, the side face is ground with a grinding stone processed in a predetermined shape and, after that, the polishing process is performed by making a polishing pad or brush come into contact with the side peripheral face while supplying a polishing solution. Refer to, for example, Japanese Unexamined Patent Application Publication No. 2004-342,307 (this counterpart is U.S. Pat. No. 6,280,294).
Since the edging process such as chambering or rounding is performed on the corner of each of a glass disk by a dedicated precision machining apparatus, it is troublesome to set the glass disks one by one. In addition, it requires a special dedicated machining apparatus, so that a problem of high cost occurs.